We didn't look around as ape-men and say, "OMG! The porpoises are wearing skirts! We've got to get some of those!"

Of course not, silly. The porpoises were busy making and wearing crowns out of seaweed!

True. When researchers exploring issues of possession gave dolphins and porpoises at one water park different toys to interact with, they were perfectly happy to share the toys like balls, but would get violent and fight each other for the right to either wear a crown, or carry a trailing loop around one fin. :-)